Path for driving-chains for velocipedes, &amp;c.



Pa'ten'ted Aug. 15,- I899.

B. LJUNGSTRUM.

PATH FOR DRIVING CHAINS FOR VELOGIPEDES, 8m.

(Application filed June 26, 1895.1

2 Sheets-Sheet 1.

(No Model.)

INVENTOH W/ TNE SSE S.

A TTOHNE YS THE Noam: PEYKRs co wuorourmu wasnmn'ron. u. c.

m; 63!,2l9. Patented Aug. l5, I899.

B. uuuesrnflm.

PATH FOR DRIVING CHAINS FOB VEILUCIPEDES, 8L0.

{Applicafioqfiled June 25, 1895.: (N0 Mo uli) 2 snug-sum z,

W/TNESSES.

' A TTOHNE Y8 1 UNITED STATES I PATENT CFFICE.

BIRGERJLJUNGSTROM, or: sTooKHoLM, SWEDEN.

PATH FOR DRIVING-CHAINS FOR VELOCIPEDES, 80C.

SPECIFICATION forming part of Letters Patent No. 631,219, dated August15, 1899.

Application filed Tune 25, 1895. Serial No. 554,000. (No model.)

To all whom it may concern:

Be it known that I, BIRGER LJUNcsTRoM, mechanician, a subject of theKing of Sweden and Norway, and a resident of 44 Grefgatan, Stockholm, inthe Kingdom of Sweden, have invented certain new and useful Improvementsin Paths for Driving-Chains for Velocipedes and other Vehicles, of whichthe following is a specification, reference being had therein to theaccompanying drawings.

This invention relates to a cam wheel or pulley for the drive-chain ordrive-rope of velocipedes provided with oscillating treadles, said Wheelor pulley being so constructed that the chain or rope acts on its shaftwith the greatest radius when the treadle, which is connected with thechain, occupies its middle position, although the said wheel or pulleymakes more than one revolution as the treadle moves from one extremeposition to the other. The advantage is thereby gained that the pulleyneed not be made of such large diameter as would otherwise be the case,

and an increased velocity ratio is thus obtained, though the winding onand off of the chain always takes place in the same plane.

Figure 1 in the accompanying drawings shows a portion of the bicycleviewed from one side; Fig. 2, the pulley and chain viewed from one side;Fig. 3, the same parts viewed from above; Fig. 4, a horizontal sectionof the pulley; Fig. 5, a transverse section of the chain, and Fig. 6 adetail of the latter.

On each side of the bicycle is a triangular treadle 1, with a pedal 2and chain 3, the latter passing to a chain-pulley 4,which by means of acoupling in known manner pulls the driving-wheel 5 along when thetreadle is depressed, but runs slack during the upward motion of thetreadle. Other pulleys '7, on which are wound the ends of a chain orrope 9, passing around the pulley 8, cause one treadle in known mannerwhile descending to pull up the opposite treadle. The pulley 4, whichforms the object of the present invention, is provided with highprojecting edges or flanges 10 and is located eccentrically on the shaft11 with reference to the circumference of said flanges or edges, whilebetween the latter the pulley, or, which amounts to the same thing,

the bottom 12 of the groove formed by the flanges, has the spiral shapeshown bya dot-- '14, serving to allow of the chain resting on theflanges 10 while it continues to wind on about to the point 15, situatednearest to the shaft, said point being located on the aforesaid flanges.The lateral projections 14 can be produced in various waysfor instance,in order not to interfere with the flexibility of the chain, by windingaround'it an iron wire bent in the shape shown in Fig. 6. The arrowindicates the direction of winding on. When the chain is wound on clearto the point 15, Fig. 2, the treadle is fully elevated, whichcorresponds to the position a of Fig. 1. When the treadle is depressed,the chain is unwound. When the chain has unwound to the point 13, itwill be farthest removed from the shaft. The treadle now occupies itsmiddle position b, Fig. 1. When the treadle is fully depressed,(position 0,) the chain is wound oi, as shown in Fig. 2, being now againclose to the shaft. The pulley has now made about one revolution and ahalf. Thus it may be seen that the desired result is gained by the shapeof the bottom 12, the presence of the flanges 10, and the projections 14of the chain, all in combination with each other. Were the bottom 12alone used, the pulley would not be able to revolve more than about onerevolution, and the pulley consequently would have to be madecorrespondingly larger if the angle of motion of the treadle were to beretained unaltered. An improved driving-gear is accordingly produced bythe device described.

Having now described my invention, what.

I claim as new, and desire to secure byLetters Patent, is-

In combination in a bicycle, the oscillating treadle, the ratchet diskor roller on the drive-wheel, said disk having a groove and.

borders or bearing edges about the same, the reciprocating drive-chainhaving projections, said projections being arranged in such a position0n the chain that they come to rest my name in the presence of twosubscribing upon said borders to carry the chain after it witnesses. hasbeen wound about a turn around the v roller or disk the said groovebeing of cam I BIRGER LJUNGS FROM 5 form with high and low parts and thechain Witnesses:

being attached at the low part near the axle. ERNST SVANQVIST, Inwitness whereof I have hereunto signed A. F. LUNDBORG.

